In U.S. Pat. No. 3,232,678, issued Feb. 1, 1966 to William G. Wilson, and assigned to the assignee of the present application, there is shown and described a brake control valve device that is substantially the same in function and operation as the brake control valve device included in the standard fluid pressure brake apparatus now in use on railway freight cars owned and operated by American railroads.
The brake control valve device shown in the above-mentioned U.S. Pat. No. 3,232,678 comprises a service valve portion embodying therein a plurality of slide, spool and disc type valves, and an emergency valve portion that has a slide-type emergency valve slidable on a flat ported valve seat and a graduating valve slidably mounted on a flat ported surface provided therefor on the side of the emergency slide valve opposite the side thereof that engages the flat ported valve seat. The manufacture and production of these slide-type valves and valve seats require considerable accurate and skillful machining which, as is readily apparent, increases the cost of the emergency valve portion of which they are an essential component.
In U.S. Pat. No. 4,045,095 issued Aug. 30, 1977 to Fred Temple, and assigned to the assignee of the present application, there is shown and described a railway car brake control valve device that is provided with a novel emergency valve portion that embodies therein five simple and inexpensive poppet-type valves that are so disposed between and operated by a pair of spaced-apart and interconnected movable abutments which are subject to atmospheric pressure on their adjacent sides and respectively to brake pipe pressure and quick action chamber pressure on their other side, as to perform the same functions as the emergency valve portion shown in the above-mentioned Wilson patent.
It is apparent that reducing the number of poppet-type valves in an emergency valve portion of a brake control valve device will effect a corresponding reduction in the cost of the emergency valve portion.
Accordingly, it is the general purpose of this invention to provide a railway car brake control valve device with a novel emergency valve portion that embodies therein only four simple and inexpensive poppet-type valves, one of which is a double seated valve, that are so disposed between and operated by a pair of spaced-apart and interconnected abutments, which are subject to atmospheric pressure on their adjacent sides and respectively to brake pipe pressure and quick action chamber pressure on their other side, as to perform the same functions as the emergency valve portion shown in the above-mentioned Temple patent.